If you wish to require a field or perform any other kind of validation, you will do so using the registration_errors filter.

3. Save the new fields

You will save the new fields by creating a callback function for the user_register action. Within this callback function, you will more than likely be using update_user_meta() to save the fields, depending on your situation and what fields you are trying to save.

Examples

The following is an example of adding first name and last name to the registration form. These fields will be required.

Add the new fields

Add the following to your copy of register-form.php anywhere between the <form> and </form> tags.